Symbolic computation

Question

2023.02.15 question paper, 

here the question is to find the universal predecessor of (q & (p | a)) . 

But while starting it's denoted as Pre.forall ( p xor q) . it should be  Pre.forall ( q & (p | a)) .is it ?

From where p xor q came?

Answer 1

Yes, that seems to be a solution from another exam problem!

Comments

Thanks for the clarification

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But actually, it is just the argument the pre-operator that is wrong, the rest seems to be allright.